Shutter for motion-picture machines.



F. A. BERG.

SHUTTEK FOR MOTiON PICTURE MACHINES.

APPucmoN min ocr. 2o. i914.

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FREDERICK A. BERG, 0F CHICAGO, ILLIVNOIS.

-SI'I'IIIIIWIER FOR MOTION-PICTURE MACHINES.

Specification of Letters Patent.

Application-filed October 30, 1914. Serial No. 869,428.

To zl vwhom t may concern.'

Be it known that I, FREDERICK A. BERG, a citizen of the United States,and a resident of the city of Chicago, county of Cook, and State ofIllinois, have invented certain new and useful Improvements in Shuttersfor Motion-Picture Machines, of which the following is a specification.y

M v invention relates to improvements in shutters for motion picturemachines and has for its object the production or' a shutter of thischaracter, through the employment of which iiickering upon the screen inthe operation of the motion picture machine will be eliminated. i

A further object is the production of a shutter which will be of simpleconstruction and efficient in use. l

Other objects will appear hereinafter.

The invention consists in the combinations and arrangements of partshereinafter.

described and claimed.

The invention will be best understood by reference to .the accompanyingdrawing forming a part of this specification, and in which- Figure l isa rear elevation of a shutter embodying my invention, Fig. 2 is a frontelevation of another form of shutter embodying my invention, and Fig. 3is a section taken online -m of Fig. 2.

The preferred form of construction as illustrated in the drawingcomprises a shutter the outline of which is of conventional design,comprising blades 1, 2 and 3. The number of blades employed in theshutter is of course unimportant inasmuch as all are identical inconstruction, and each in itself embodies the invention. The blades l',2 and 3 are formed of glass, mica or other suitable transparent orsemi-transparent material, saidblades, in the form shown in Fig. l beingformed integral. The central portion of the integral body thus formed isprovided with an opening for the accommodation of the rotary spindle towhich the shutter is attached, a plurality of smaller openings beingprovided around the central opening for the accommodation of securingdevices.. If desired however the shutter blades may be formed separateas shown in Figs. 2 and 3 where said blades, indicated as i. 2 and 3 areconnected with a central metallic portion 4 by means of screws 5 andcooperating nuts 6.

Each of the blades of tte shutter is provided at its-front side with acoating 7 composed of particles of lustrous material, such asquick-silver or mercury; or silver, gold, aluminum or bronze paintadapted, when applied to the shutter, to crystallize or form into anuneven surface presenting myriads of minute bright, shining facesadapted to.

reflect light impinging thereon in all directions. Tlie opposite side ofeach shutter blade is ground, frost-ed, etched or sand blasted, and theedge portions 8 of the Jfront side of said blades are correspondinglyground, frosted, etched or sand blasted, before the applicationiof thecoating 7 in order to render said edge portions less transparent andmore opaque than the central portion of the blade.

lVith the construction set forth a shutter is produced which issemi-transparent or translucent, permitting of the passage therethroughof approximately sixty-six per cent. of the light from the source ofillumination when `the shutter is in traversing'position. However.through the coating of lustrous material on one side of the shutter andthe frosted or ground formation of the other side, the light from thesource of illumiation will be reiiect'ed in all directions bythe myriadsof minute lustrous or reiecting surfaces which are constituted by the'particles composing the lustrous coating and which result from thegrinding or frosting of the surface of the glass or other materialemployed so as to so thoroughly diffuse the light that the movement ortravel of the film such as occurs, as is known, when the shutter is'intraversing position, will be unnoticed upon the screen. It is of courseknown that filckering 'upon the screen is caused by the. alternatedarkening and lighting of the screen which occurs by reason of thepassage of the shutter in front of the lens. The darkening of the screenresults from the use of an opaque shutter such as is in general use atthe present time. However with a shutter of the construction ret forth,the screen instead of being blackenbd or totally darkened through thetraversing position of the shutter, will be simply darkened slightly'toa soft gray or silver white. The total darkening of the screen beingeliminated, the ickering will necessarily be done away with.

It is understood that shutters of a semitransparent or translucentformation have been used before, but the same have been Patented Nov;16,1915. I

unsuccessful in that, when in use, the movement of the ihn has beentransferred therethrough onto the screen thereby resulting in theproduction of a hazy streaked picture on the screen, the streaks beingthe result of the movement of the film transferred through the shutteras will be readily understood. l Up to thc present the failui'e of asemi-transparent or translucent shutter has been due to the fact thatthe light has not been thoroughly diffused in its passage through theshutter, the surface of shutters of this class heretofore used nothaving been coated with a lustrous material or frosted to produce themyriads ot reflecting surfaces above referred to. Through theconstruction employed the thorough diffusion of the light passingthrough the shutter is accomplished with the result that the movement ofthe film .is not all apparent upon the screen. Very good results areobtained by simply coating the shutter with the lustrous material, ithaving beenfound however that the best results are obtained when thcshutter is provided with a coating of lustrous materialen one side andwith the other side ground or frosted.

It has been found through experiment that by frosting the radial edgeportions Sat the fiont side of the shutter blades so aS to render saidportions less transparent and more opaque, the pictures projected ontothe screen are rendered free from haze and travel ghosts or in otherwords more distinct and clear cut.I

lVhile I have illustrated and described the preferred form ofconstruction for cal'` modifications as come within the scope of .theappended claims.

f Having described my invention what I claim as new and `desire tosecure by Letters Patent is:

l. A'shutter for motion picture machines comprising a transparent orsemi-transparent body provided with a coating of lustrous materialadapted to diuse light impinging thereon, y substantially as described.

2. A shutter for motion picture machines comprising a transparent orsemi-transparent body provided on one side with a coating of lustrousmaterial adapted to diffuse light in'ipinging thereon, substantially asdescribed.

3. A shutter for motion picture machines comprising a transparentorsemi-transparent body provided on one side with a coating of lustrousmaterial and having its opposite side ground oi frosted, substantiallyas described. g

4. A shutter foi` motion picture machines comprising a transparent orsemi-transparent sector shaped body provided with a coating of lustrousmaterial and having its radial edge portions less transparent than theremainder of said body, vsubstantially as described.

5. A shutter for motion picture machine comprising a transparent orsemi-traiisparen't sector shaped body provided on one side with acoating of lustrous material, the opposite side of said body beingground or frosted, and the radial edge poit-ioiis of said body beingless transparent, than the remainder thereof, substantially asdescribed.

6. A shutter for motion picture machines comprising a transparent orsenii-transpaient sector shaped body provided on one side with a coatingof lustrous material, the radial edge portions of said side of said bodybeing ground or frosted, and the opposite side ,of/said body beingground or frosted, substantially as described.

7. A shutter forinotion picture machines comprising a transparent orsemi-transparent body, the outer surface of which is Coniposed of agreat number of minute reflecting surfaces adapted to reficct lightiinpinging thereon in all directions, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FREDERICK A. BERG. lVitnesses I Josiira l. H. Io'i" ARTHUR A. OLsox.

